Recently, blood flow has been improved by widening a lesion (stenosed portion) of the coronary artery with a balloon catheter, in treatment of, for example, acute myocardial infarction and angina pectoris, percutaneous coronary intervention (percutaneous transluminal coronary angioplasty). For example, refer to Japanese Patent Application Publication No. 2008-501408. Treatment using a balloon catheter may also be performed to improve a lesion formed inside other blood vessels, the bile duct, the trachea, the esophagus, the urethra, and other body lumens.
Generally, a balloon catheter includes a long shaft and a balloon on the distal side of the shaft. The balloon inflates in the radial direction (i.e., expands radially outward by inflation). The balloon catheter is delivered to a stenosed portion in a body after a preceding guide wire is inserted through to the stenosed portion. When the balloon is positioned at the target stenosed portion, the balloon is inflated by pressure-feeding an inflation fluid into the balloon. The stenosed portion can thus be widened.
In order to effectively treat a lesion, the balloon of the balloon catheter is required to have sufficient strength to possess a desired balloon shape when being maximally inflated to widen the lesion. Therefore, in order to apply high-pressure resistance, low compliance properties, and the like to a balloon, a configuration has been proposed in the related art in which a net-shaped reinforcement member is provided in a wall configuring the balloon. For example, refer to Japanese Patent Application Publication No. 2008-501408.
A balloon catheter transports the balloon to a lesion inside the body lumen. Since the balloon needs to pass through the inside of the bent body lumen while being transported, the balloon is required to have flexibility (i.e., be flexible) to follow the bent state of the body lumen. The technology in the related art discussed above, in which a reinforcement member is provided in the wall of the balloon, however, has a problem in flexibility. The problem in flexibility arises because the reinforcement member is integrally fixed to the balloon, and there is no degree of freedom for movement relative to the wall of the balloon. It is thus difficult to apply sufficient flexibility to the balloon.